1. Field of the Invention
This invention relates to an optical disc apparatus for recording and/or reproducing information signals using e.g., an optical head.
2. Description of the Related Art
Conventionally, an optical disc apparatus, adapted for recording and/or reproducing an optical disc rotatably accommodated in a disc cartridge, has a recording/reproducing unit for an optical disc in the main body unit of the apparatus. On a base block of the recording/reproducing unit are assembled a disc rotation unit for rotationally driving the optical disc and an optical head for recording and/or reproducing information signals. This optical head faces the recording/reproducing unit via an opening formed in the base block and is fed along the radius of the optical disc by a feed unit.
If a disc cartridge is loaded on the recording/reproducing unit of the optical disc apparatus, a shutter member, adapted for closing an aperture formed in the disc cartridge for partially exposing the optical disc accommodated in the cartridge to outside, is moved to open the aperture in the disc cartridge. In this optical disc apparatus, the disc rotation unit runs the optical disc in rotation, while the optical head illuminates the light beam on the optical disc facing the aperture formed in the disc cartridge to record or reproduce information signals.
That is, if the disc cartridge is loaded on the recording/reproducing unit of the optical disc apparatus, the shutter member is moved to and kept at the position of opening the aperture in the disc cartridge.
Meanwhile, there is such an optical disc in which, for increasing the recording capacity for information signals for recording, a signal recording layer is formed on a disc substrate, and a light-transmitting layer about 0.1 mm in thickness is formed on this signal recording layer, with the side of the light-transmitting layer of the optical disc being used as a signal recording surface. For this optical disc, an optical pickup device is used which employs an objective lens having the numerical aperture NA of 0.7 or higher and a wavelength not larger than 680 nm. With this optical disc device, the separation between the signal recording surface of the optical disc and the objective lens, that is the working distance, is set to 560 m or less. With such optical disc in which the optical head is extremely close to the signal recording surface, there are occasions wherein, if contaminants such as dust and dirt are affixed to the signal recording surface of the optical disc, these contaminants are affixed to the objective lens of the optical pickup apparatus to contaminate the objective lens.